added info re --log

reference/hde/commandline-arguments.md

@@ -13,6 +13,7 @@ Replace the default global location for NuGets|`--nuget-path` + path to director
 List of package repositories used by VL to lookup packages. Most useful, when [working on libraries](../extending/contributing.md).|`--package-repositories` + a semi-colon separated list of package repository directories
 Tell the exporter to add a path to the generated NuGet.config file, which in turn will be used by dotnet to build the generated project|`--export-package-sources` + path to directory with .nupkg files
 **As of 5.0:** Opt-out of the read-only default for libraries in order to work on them. For details, see [Editable Packages](../language/compilation.md#editable-packages).|`--editable-packages` + a semi-colon separated list of packages. Glob patterns are allowed, e.g. VL.IO.*
+**As of 5.3:** Log issues during startup to %UserProfile%\Documents\vvvv\gamma\vvvv.log |`--log`
 
 Example:
 

reference/hde/debugging-log.md

@@ -33,4 +33,9 @@ The interesting thing with logging is that you can also route logs to any [loggi
 
 When exporting your application, by default you've now lost the ability to view your log messages, since the above Log window is part of vvvv itself and not your app.
 
-Yes you still have all the possibilities to use any thirdparty log providers but you may also want to have a log window as part of your application, see "HowTo Use the log view in an exported application" for how to set this up.
+Yes you still have all the possibilities to use any thirdparty log providers but you may also want to have a log window as part of your application, see "HowTo Use the log view in an exported application" for how to set this up.
+
+## Log issues during startup of vvvv
+If you encounter issues already while vvvv itself is starting up, run vvvv.exe using the `--log` commandline argument and then inspect the vvvv.log file being created in:
+
+    %UserProfile%\Documents\vvvv\gamma\